Toric lens tool



March 5, 1963 H. J. KRATT ETAL TORIC LENS TOOL 2 Sheets-Sheet 1 Filed April 17, 1961 INVENTORS 20 3y 7 W ATTORNEYS.

March 5, 1963 H. J. KRATT EI'AL TORIC LENS TOOL 2 Sheets-Sheet 2 Filed April 17, 1961 Mar. 5, 1%53 lice 't Lauderdale, Fla Leonard assignors to The Plastic Conlll, a corporation of relates to a tool for holding a l ns blank that spherical cutting, grinding and/ or Qur invention in such manner polishing of a surface of the blank will result in a final surface which is toric in shape, our tool being particularly adaptable in the manufacture of corneal type, contact lenses.

One object of the invention is to provide a toric lens tool having means to hold a lens blank in such manner that two opposite peripheral portions thereof are held in a d ferent plane than two other opposite peripheral portions thereoi at right angles to the two first portions, whereby the lens blank is warped; and thereupon by cutting, grinding and/ or polishing a surface of the lens blank to spherical shape, that surface will be toric in shape when the lens blank is released from the tool.

Another object is to provide a lens blank holding tool having means to accurately align a lens blank so that the blank is concentric relative to the tool and a base curve for the lens can be cut or ground in the blank and will be concentric to the blank itself so that subsequent cutting or grinding of a spherical power curve opposite the base curve may be accomplished with assurance that there will be accurate optical alignment of the two curves and at the same time minimizing the time equired for completely cutting or grinding the lens.

Still another object is to provide separate means for holding the edge of the lens blank at two pairs of diametrically opposite points, one pair of points being crosswise of the other and the pairs of points being in dififerent planes so as to warp the lens blank before a cutting, grinding and/or finishing operation on one surface thereof whereby when that surface is finished to a spheri al shape, it wil return to a toric shape when released from our lens holding means.

A in r object is to provide means of calibration to indicate the adjustm nt of the tool for toric surfaces of different dioptric rabetween the major and minor curvatures of the toric lens surface.

Still a further object is to provide a supporting and centering ring for the lens which is acted upon by the tool, being warped t and in turn warping the lens blank as the tool is adjusted for the desired degree of such dioptric ratio.

With these and other objects in view, our invention ls sts in the construction, arrangement and combination of he various parts of our toric lens tool, whereby i above contemplated are 'ned, as hereinafter -v set forth, pointed out ace is an enlarged and ex our toric l 7. a front elevation o r tori k held hereby in a COllclI a -e, the parts Jed from the F1 tow l the viewer.

Flu view on the line 3-3 of 1G. osition tor cutting a base curve in the lens, the ladder being adjusted so that the lensi not warped.

4 a side elevation, partly in section, of our tool adiusted to receive a lens blank and illustrating the insertion of such blank in the tool.

5 is a sectional view similar to FIG. 3 but rotated 90 and shows the cooperation of the lathe spindle and collet with certain portions of the lens holder to axially align them relative to each other and thereby accurately center the lens blank with respect to the axis of rotation of the tool.

Pi-GS. 6 and 7 are enlarged sectional views similar to FIGS. 3 and 5 respectively showing the tool adjusted for Warping the lens blank; and

FIG. 8 is a sectional view similar to FIG. 7 showing the tool and lens blank associated with a polishing tool and pin for polishing the base curve of the lens after it has been cut or ground.

On the accompanying drawings we have used the following reference characters to indicate in general a lens blank and the four parts that form our toric lens tool and reading, in FIG. 1, from top to bottom:

B-Lens blank R-Warping and supporting ring WWarping bar TToo1 body S-Adjusting screw The lens blank B and certain tools for forming a nontoric lens therefrom are shown and claimed in the copending applications of Henry J. Kratt, Serial No. 24,473, filed April 25, 1960, and Serial No. 48,126, filed August 8, 1960.

The present invention has to do with a lens holding tool so designed that the base (or posterior) curve for the lens can be cut, ground and/ or polished with cylinder and therefore has a toric shape. The copcnding application of Kratt, Serial No. 51,167, filed August 22, 1960 shows and claims a somewhat similar tool for forming a toric power (or anterior) curve on a lens. A toric base curve as herein disclosed is accomplished by warping the lens blank.

A tool body T is provided with a pair of diametrically opposite jaws to and a bore 12 having a threaded portion The adjusting screw S has a screw portion 16 entering the threads 1 and a knob 18 provided with graduations 26 The graduations may bear suitable indicia (not shown) to be read against a hairline 24 of a transparent pointer 2-2 extending from the tool body T. A set screw as is provided in the body T to bear against a soft metal slug which in turn bears against the threads of the adjusting screw 16 for retaining the adjustment thereof. The body T is further provided with a cross slot 36 adapted to receive the warping bar W. The bar in turn has a central clearance notch 32, at the ends of which supporting shoulders are provided that terminate in circumference engaging shoulders 36 for the warping and supporting ring it.

The ring R preferably has a cone seat 33 to fit a cone surface it; of the lens blank B, which blank also has a. flange 32. in FIGS. 3 and 5 a lathe spindle 44 is shown having a tapered bore to receive a collet 45 of the usual split type (3 splits being illustrated at 43). The collet of course is adapted to be drawn into the spindle to contract around the lens holding tool shown in PEG. 1 when it is assembled with a lens blank therein illustrated in these two figures wherein no attempt how- Referring to HG. 4 the manner of assembly of the tool to hold a blank B is illustrated. The adjusting screw S is in such position as to clear the bottom of the oss slot so that the warping bar W can be slid into POSlLlO'l'I as indicated by the arrow 5'3. It will be noted that the blank B has been seated in the ring R and the ring in turn positioned for confinement between the shoulders 36 ac-varev and supported on the shoulders 3 3. top of blank B isle: of the ws is? accordn "ly the bar W can be slid all be way as to the po .r shown in with th ends of the bar substantially coincident h the circurnference of the tool body '1. When thus positioned the blank 13 is located vertically in FIG. 2 by the facing surfaces 33 of the javs l and horizontally by the shoulders of the .vlicreuoon the screw S may be tightened a5, ist the bar W.

tool and the lens blank are then i; erted in the collet while it is loosened, whereupon tightening of the collet by drawing it into the spindle 44 results in final accurate positioning of the bar W with respect to the tool body T as the jaws of the collet are urawn into engagement with the tool. H65. 3 and 5 show the screw S tightened only enough to hold the lens whereas actually it will be tightened to the proper degree to form the desired toric base curve as indicated by the graduations 2i and the hairline 24. Upon contact of the threaded portion of the screw S with the lower surface of the bar W in FIGS. 3 and 5 the lens blank will be held between the bar, the jaws 1% and the ring R but not warped. Furthe;- tightening will eiiect warpage as shown in FIGS. 6 and 7 because the jaws fit? in FIG. 6 are holding the flange d2 of the blank B against any further movement whereas the bar W is through its shoulders 34 and the ring R, pressing against the blank intermediate the jaws, thus warping the ring and blank from a non-warped or straight position as in FIG. 3 to the outwardly bowed shape as shown in FIG. 6. Looking at the cross section at right angles as in FIG. 7 the inwardly bowed shape of the lens and ring under the jaws it? is shown because of the upward movement of the bar W past a non-warped shape as already referred to in FIG. 5. The warped lens blank is now ready for cutting after it is chucked in the lathe collet 46.

FIG. 3 shows the manner of cutting, a lathe bit 52 being shown in a lathe bit holder 54-. The lathe bit is adapted to cut a base curve 55 in the lens blank B on a suitable radius indicated r. For this purpose the lathe bit is so mounted as to swing about a vertical axis indicated by a dot 53 and of course may be adjusted for any reqrired length of radius as r.

The lathe bit 52, swinging about the center 5'55 and through an arc of cut indicated at 5%, will cut the surface of the warped lens spherical as it is held by our toric lens tool, and such spherical surfaces are also idicate at 5% in FIGS. 6 and '7. it is now obvious that ii the lens blank is released from the position it assumes in PEG. 6 by loosening the adjusting screw S the blank will return to its original sh pc and the base curve 5r; will assume a sharper curvature as indicated by the dot-anddash line and will constitute the minor curvature of toric surface whereas release from the p iiicn in FIG. 7 will result in the base curve t re si in this position than the under surface iswn flattoning to the dot-anddash curvature ll'ldl-C..id at (part of the lens b nk being l ft unsectioned to show 56* more clearly) wl or will constitute the curvature of the toric surface of the lens. Thereafter the opposite or power surface of the blank may be formed as disclosed in the above identified copending patent applications.

release oi the lens from the tool holder however the base curve 5% (o 3 remains warped) is toric lens tool with the collet and associated was a po shing tool d2 having a herrnispherica head provided with padding of rnoleskin, felt, velve or the like charged with a uitable polishing agent such as sta-nnic oxide and water, and with a polishing pin 5'5 of a pol shing machine, the point of which oscillates on an are do while the tool 62 rotates as indicated by the arrow 79. "Ihrs the sur ace 55 is polished spherical so that when the lens blank s re eased from the tool it has a pol: ned toric surface 5- 56 the minor and major curvatures of which are according to th indicated arcs se and dd in FZJS. 6 and 7. The screw the (not shown) at a suitable speed for polishing. Acco dingly one curvature will be sharper than the other en the bi is released from the tool and thereupon u ns to its original shape. Thus a certain dioptric difference to produce a toric base curvature (or cylinder) in the lens has been formed into the posterior surface oi the lens.

A ally H63. 6 and 7 the degree of warping is so ewhat exaggerated, as but a few thousandths of an 'inch movement is all that is required. The graduations 2% serve as a micrometer scale which may be calibrated as desired in either thousandths of an inch difr'erence or diopters or dillereuce.

From the foregoing specification it will be obvious that we have provided a tool for holding lens blanks in such manner that a surface of the blank can be spherically cut or ground and polished, yet when the blank is released from the tool that surface will be toric in shape. At the sarne time the dioptric difference between the major and rninor curvature of the toric surface may be micrcmetrically adjusted and conveniently indicated as to such adjust. rent by cooperation of the graduations 2i and hairline 2 which indicate the degree of warpin Some changes may be made in the construction and arrangement or" the parts of our toric lens tool without departing from the real spirit and purpose of our invention, and it is our intention to cover by our claims any modified forms of structure or use of mechanical equivalents which may reasonably be included within their scope.

We claim as our invention:

1. in a toric lens tool of the character disclosed, a body having a pair of opposite lens blank edge engaging jaws, said body having crosswise of said jaws a slot, a warping bar slidably received in said slot and having a pair of lens blank edge engaging shoulders, a supporting and warping ring interposed between said shoulders and the blank, and an adjusting screw carried by said body and engageable with said warping bar to move said bar axially of said body and in a direction for warping the lens blank between said jaws and said shoulders.

2. in a toric lens tool of the character disclosed, a body having a pair of opposite lens blank edge engaging jaws, said body having crosswise of said jaws a slot, at warping bar slidably received in said slot and having a pair of lens edge engaging shoulders, a supporting and Warping ring interposed between said shoulders and the blank, an adjusting screw carried by said body and engageable with said warping bar to move said bar axially of said body and in a direction for warping the lens blank between said jaws and said shoulders, and calibration means for said adjusting screw.

3. A toric lens tool comprising a body having a pair of opposite lens blank edge engaging jaws, said body having crosswise thereof a slot, at warping bar slidably received in said slot and having a pair of lens blank edge engaging shoulders intermediate said jaws, and an adjusting screw carried by said body and engageable with said warping bar to move the bar axially of the body an in a direction for warping the lens blank between said jaws and said shoulders.

A toric lens tool comprising a body having a pair of opp-o ite lens blank edge engaging jaws, said body having crosswise thereof a slot, a warping bar slidably received 'n sale slot and having a pair of lens blank edge engaging s oulders intermediate said jaws, an adjusting screw carby said body and engageable with said warping bar to move th bar axially of the body and in a direction warping the lens blank between said jaws and said ulders, and calibration means for said adjusting screw.

edge engaging shoulders for the opposite surface of the lens blank, said shoulders being circumferentially intermediate said jaws, a supporting and warping ring interposed between said shoulders and the blank and an adjusting screw carried by said body and engageable with said warping bar to move said bar axially of said body for warping the lens blank between said jaws and said shoulders.

6. In a toric lens tool, a cylindrical body having a pair of opposite lens blank edge engaging jaws for one surface of a lens blank, a warping bar having a pair of lens blank edge engaging shoulders for the opposite surface of the lens blank, said shoulder being circumferentially intermediate said jaws, and an adjusting screw carried by said body and engageable with said warping bar to move said bar axially of said body for warping the lens blank between said jaws and said shoulders.

7. In a toric lens tool, a cylindrical body having a pair of opposite lens blank edge engaging jaws for one surface of a lens blank, a warping bar having a pair of lens blank edge engaging shoulders for the opposite surface of the lens blank, said shoulders being circumferentially intermediate said jaws and the length of said bar being coincident with the diameter of said body, a supporting and warping ring interposed between said shoulders and the blank and an adjusting screw carried by said body and engageable with said warping bar to move said bar axially of said body for warping the lens blank between said jaws and said shoulders.

8. In a toric lens tool, a cylindrical body having a pair of opposite lens blank edge engaging jaws for one surface of a lens blank, a warping bar having a pair of lens blank edge engaging shoulders for the opposite surface of the lens blank, said shoulders being circumferentially intermediate said jaws and the length of said bar being coincident with the diameter of said body, and an adjusting screw carried by said body and engageable with said warping bar to move said bar axially of said body for warping the lens blank between said jaws and said shoulders.

9. A toric lens tool comprising a cylindrical body having a pair of opposite lens blank edge engaging jaws, said body having crosswise thereof a slot, a warping bar of substantially the same length as the diameter of said body, slidably received in said slot and having a pair of lens blank edge engaging shoulders intermediate said jaws, and an adjusting screw carried by said body and engageable with said warping bar to move the bar axially of the body and in a direction for warping the lens blank between said jaws and said shoulders.

10. In a toric lens tool, a cylindrical body for reception in a lathe collet, said body having a pair of opposite lens blank edge engaging jaws, said body having crosswise of said jaws a slot, a warping bar slidably received in said slot and having a pair of lens blank edge engaging shoulders, a supporting and warping ring interposed between said shoulders and the blank, means to center said bar and said ring relative to said body, and an adjusting screw carried by said body and engageable with said warping bar to move said bar axially of said body in a direction for warping the lens blank between said jaws and said shoulders.

11. In a toric lens tool, a cylindrical body having a pair of opposite lens blank edge engaging jaws for one surface of a lens blank, a warping bar having a pair of lens blank edge engaging shoulders for the opposite surface of the lens blank, said shoulder being circumferentially intermediate said jaws, and an adjusting screw carried by said body and engageable with said warping bar to move said bar axially of said body for warping the lens blank between said jaws and said shoulders, said adjusting screw having a polishing pin seat located on the axis of said body and at the end of said tool opposite said jaws and warping bar.

References (liter! in the file of this patent UNITED STATES PATENTS 1,022,761 Stvanek Apr. 9, 1912 1,412,170 Dixon Apr. 11, 1922 1,455,438 Hill May 15, 1923 2,301,035 Golderer Nov. 3, 1942 2,443,895 Day et al June 22, 1948 2,872,198 Motz Feb. 3, 1959 2,918,291 Plantas Dec. 22, 1959 FOREIGN PATENTS 601,326 Great Britain May 4, 1948 

1. IN A TORIC LENS TOOL OF THE CHARACTER DISCLOSED, A BODY HAVING A PAIR OF OPPOSITE LENS BLANK EDGE ENGAGING JAWS, SAID BODY HAVING CROSSWISE OF SAID JAWS A SLOT, A WARPING BAR SLIDABLY RECEIVED IN SAID SLOT AND HAVING A PAIR OF LENS BLANK EDGE ENGAGING SHOULDERS, A SUPPORTING AND WARPING RING INTERPOSED BETWEEN SAID SHOULDERS AND THE BLANK, AND AN ADJUSTING SCREW CARRIED BY SAID BODY AND ENGAGEABLE WITH SAID WARPING BAR TO MOVE SAID BAR AXIALLY OF SAID BODY AND IN A DIRECTION FOR WARPING THE LENS BLANK BETWEEN SAID JAWS AND SAID SHOULDERS. 